1. Field
Exemplary embodiments of the present invention relate to an optical patterning mask and a method of fabricating a display device using the same.
2. Discussion of the Background
An organic light-emitting display device (OLED) is a self light-emitting type display device that has garnered much attention as a next-generation display device because of its wide viewing angle, excellent contrast, and fast response rate characteristics.
The organic light-emitting display device may include an anode electrode, a cathode electrode, and an organic light-emitting layer (EML) provided between the anode electrode and the cathode electrode and formed of an organic light-emitting material. In response to a positive voltage and a negative voltage applied to the anode electrode and the cathode electrode, respectively, holes from the anode electrode may move to the EML through a hole injection layer (HIL) and a hole transport layer (HTL), and electrons from the cathode electrode may move to the EML through an electron injection layer (EIL) and an electron transport layer (ETL). The holes and the electrons may be recombined together in the EML. As the holes and the electrons recombine, excitons may be generated. When excitons transition from an excited state to a ground state, the EML may emit light, and as a result, an image may be displayed.
In the manufacture of the organic light-emitting display device, the HIL, the HTL, the EML, the ETL and the EIL may be formed by an inkjet printing method, a nozzle printing method, a deposition method using a metal mask, or a transfer method using heat or laser light.
The transfer method using heat or laser light, in particular, may allow fine patterning of the HIL, the HTL, the EML, the ETL, and the EIL. Accordingly, a high-resolution organic light-emitting display device may be produced.
According to the transfer method using heat or laser light, light emitted from a light source may be absorbed and converted into thermal energy by a light-to-heat conversion layer of a donor substrate, and a transfer layer may be transferred onto a predetermined device substrate by the thermal energy so as to form a pattern layer. For example, an EML material layer may be transferred onto a substrate of an organic light-emitting display device, and as a result, an EML may be formed.
However, the temperature of the thermal energy output from the light-to-heat conversion layer when absorbing light may not be uniform throughout the light-to-heat conversion layer. That is, the temperature of the thermal energy may increase only in a particular part of the light-to-heat conversion layer, for example, in a middle part of the light-to-heat conversion layer. Thus the thickness of the EML formed by transferring the EML material layer onto the substrate of the organic light-emitting display device may become irregular. As a result, the display quality of the organic light-emitting display device may deteriorate.
In addition, when the donor substrate is reused, the transfer material of the transfer layer may be accumulated on the donor substrate, and as a result, EMLs may be formed in different shapes and thicknesses. Accordingly, the reproducibility from repeated use of the donor substrate may deteriorate.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.